This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from the inventor""s application CONDUCTIVE GASKET FOR IMPROVING CONTACT RELIABILITY filed with the Korean Industrial Property Office on Nov. 22, 1999 and there duly assigned Ser. No. 25660/1999.
1. Field of the Invention
This invention relates to a conductive gasket for shielding electromagnetic radiation. More specifically, the conductive gasket forms a reliable conduction path between conductive members.
2. Description of the Related Art
Electromagnetic interference (EMI) is an undesirable electric disturbance that is induced or radiated from electric or electronic devices. Radio frequency interference (RFI) is generally referred to as EMI. More accurately, however, RFI is limited to the radio frequency part of the electronic spectrum, typically from 10 kHz to 10 GHz.
In order to shield an electrical or electronic device from such EMI/RFI, it is known to provide a conductive gasket capable of reducing energy level by absorbing or reflecting EMI/RFI. Such a conductive gasket forms a conduction path between an EMI/RFI generator and ground to provide shielding against generated EMI/RFI energy. Conductive gaskets have been continuously developed in a variety of shapes. A widely used conductive gasket is shown in FIG. 1.
However, such a conventional conductive gasket suffers from the following problem in actual use. A clearance may form between the edge of the gasket and the conductive surface to which it is attached, creating resistance. To overcome such a problem, use of a conductive pressure-sensitive adhesive (PSA) may be used. However, the conductive PSA is expensive and has an inferior adhesive strength to a non-conductive PSA. This results in increased manufacturing costs of the gasket and deteriorated adhering efficiency.
Moreover, for use in a minute-sized electronic device, the width of the gasket is necessarily narrowed. Then, the width of the PSA attached to the gasket must be accordingly narrowed. Yet, a predetermined amount of electric contact portion between the conductive member and the conductive cloth of the gasket is needed. When the width of the PSA is extremely narrowed, it is difficult to firmly attach the gasket to the conductive member. This results in poor manufacturing efficiency.
It is therefore an object of the present invention to provide a conductive gasket for improving EMI/RFI shielding efficiency and contact reliability, where the PSA is not necessarily conductive.
It is another object of the present invention to provide a conductive gasket for enhancing productivity and lowering manufacturing costs.
To achieve the above and the other objects of the present invention, the invention provides a conductive gasket including: a non-conductive, elastic core extending in a longitudinal direction; a flexible, electrically conductive cloth enclosing the outer surface of the core; a hot-melt adhesive inserted between the core and the conductive cloth to attach the core to the conductive cloth; a pressure sensitive adhesive (PSA) tape attached to the conductive cloth longitudinally in such a manner that the PSA tape covers the end portions of the conductive cloth; and a ridge formed on the PSA tape attached side of the conductive cloth.
According to an embodiment of the present invention, the ridge is formed by folding a portion of the conductive cloth over another portion and the ridge protrudes beyond the other portion. According to another embodiment of the present invention, the core is formed in such a manner that a portion thereof protrudes beyond the other portion.
The PSA may be conductive or non-conductive. For lower manufacturing costs and enhanced adhesion, it is desirable to use a non-conductive PSA.